This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Tuberculosis (TB) is the current leading cause of death for AIDS patients. Its pathogen, Mycobacterium tuberculosis, infects one-third of the world population. Cell wall lipids are essential for the survival, virulence and latency development of M. tuberculosis. Three acyl-CoA carboxylases (ACCases), AccD4, AccD5 and AccD6, are important for cell wall lipid biosynthesis, whose disruption leads to pathogen death. The lack of ACCase crystal structures has greatly hampered the drug design effort of new tuberculosis drugs that target at ACCase. SSRL beam time to solve crystal structures of multi-subunit ACCase will be scientifically significant, because it will lead to the first ever multi-subunit ACCase complex crystal structure, and help define the biological roles of AccD4-6. Its medical significance lies in structure-based drug screening based on ACCase crystal structures.